U.S. patent number 6,761,030 [Application Number 10/149,016] was granted by the patent office on 2004-07-13 for waste heat recovery device of multi-cylinder internal combustion engine.
This patent grant is currently assigned to Honda Giken Kogyo Kabushiki Kaisha. Invention is credited to Tsuneo Endoh, Yuichi Itoh, Hiroyuki Niikura, Naoki Ohta.
United States Patent |
6,761,030 |
Niikura , et al. |
July 13, 2004 |
Waste heat recovery device of multi-cylinder internal combustion
engine
Abstract
A waste heat recovering device for a multi-cylinder internal
combustion engine, wherein among a plurality of exhaust pipes
extending from cylinders of a multi-cylinder internal combustion
engine, a plurality of exhaust pipes unlikely to cause exhaust
interference are collected to form one or more collecting pipes. A
heat exchanger for recovering heat of exhaust gas is provided in
the one or more collecting pipes. Therefore, a waste heat
recovering device can be provided, in which the number of heat
exchangers is reduced compared to the number of cylinders of the
multi-cylinder internal combustion engine to reduce rest periods of
the heat exchanger and reduce spaces occupied by the heat
exchanger.
Inventors: |
Niikura; Hiroyuki (Wako,
JP), Endoh; Tsuneo (Wako, JP), Itoh;
Yuichi (Wako, JP), Ohta; Naoki (Wako,
JP) |
Assignee: |
Honda Giken Kogyo Kabushiki
Kaisha (Tokyo, JP)
|
Family
ID: |
18420128 |
Appl.
No.: |
10/149,016 |
Filed: |
October 28, 2002 |
PCT
Filed: |
December 08, 2000 |
PCT No.: |
PCT/JP00/08703 |
PCT
Pub. No.: |
WO01/42626 |
PCT
Pub. Date: |
June 14, 2001 |
Foreign Application Priority Data
|
|
|
|
|
Dec 10, 1999 [JP] |
|
|
11/351862 |
|
Current U.S.
Class: |
60/618; 60/614;
60/616 |
Current CPC
Class: |
F01N
3/0205 (20130101); F01N 3/02 (20130101); F01N
13/08 (20130101); F01N 13/011 (20140603); F01N
5/02 (20130101); F02G 5/02 (20130101); Y02T
10/12 (20130101); Y02T 10/16 (20130101); Y02T
10/166 (20130101); Y02T 10/20 (20130101) |
Current International
Class: |
F01N
7/08 (20060101); F01N 5/00 (20060101); F01N
5/02 (20060101); F02G 5/00 (20060101); F02G
5/02 (20060101); F01N 3/02 (20060101); F01N
7/00 (20060101); F01N 7/04 (20060101); F02G
003/00 () |
Field of
Search: |
;60/614,616,618 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
56-156407 |
|
Dec 1981 |
|
JP |
|
3-151519 |
|
Jun 1991 |
|
JP |
|
4-353212 |
|
Dec 1992 |
|
JP |
|
5-340241 |
|
Dec 1993 |
|
JP |
|
7-224727 |
|
Aug 1995 |
|
JP |
|
7-259548 |
|
Oct 1995 |
|
JP |
|
Primary Examiner: Nguyen; Hoang
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch, LLP
Parent Case Text
This application is the national phase under 35 U.S.C. .sctn. 371
of PCT International Application No. PCT/JP00/08703 which has an
International filing date of Dec. 8, 2000, which designated the
United States of America.
Claims
What is claimed is:
1. A waste heat recovering device for a multi-cylinder internal
combustion engine, comprising: n, where n is greater than 1,
exhaust pipes extending respectively from n cylinders of the
multi-cylinder internal combustion engine; at least one and less
than n collecting pipes for collecting exhaust from said n exhaust
pipes; a heat exchanger for recovering heat of exhaust gas being
provided in each of said collecting pipes; where each of said
collecting pipes are connected to exhaust pipes of cylinders spaced
in firing order so as to reduce exhaust interference and situated
at a distance from corresponding cylinders which is short enough to
normally cause exhaust interference; where a number of heat
exchangers provided is less than the number n of the cylinders and
a total of periods when each heat exchanger receives a supply of
exhaust gas per cycle of the engine is longer than a period of one
exhaust stroke of each cylinder.
2. A waste heat recovering device for a multi-cylinder internal
combustion engine according to claim 1, further comprising a
Rankine cycle system having an evaporator for generating a vapor
with a raised pressure, using exhaust gas as a heat source; an
expander for producing output by expansion of the vapor; a
condenser for liquefying a vapor, which is exhausted from the
expander, with a dropped pressure after said expansion; and a
supply pump for supplying liquid from the condenser to said
evaporator, said heat exchanger functioning as said evaporator.
Description
FIELD OF THE INVENTION
The present invention relates to a waste heat recovering device for
a multi-cylinder internal combustion engine.
BACKGROUND ART
Known as waste heat recovering devices of this type are a device
including a heat exchanger in each of a plurality of exhaust pipes
extending from cylinders of a multi-cylinder internal combustion
engine (see Japanese Patent Application Laid-open No. 56-156407,
for example) and a device including a heat exchanger in a
collecting pipe which is collection of a plurality of exhaust pipes
extending from cylinders of a multi-cylinder internal combustion
engine (see Japanese Patent Application Laid-open No. 5-340241, for
example).
However, the former needs as many heat exchangers as the cylinders,
and thus has a problem that, for example, after operation of a heat
exchanger in the first cylinder in firing order, further operation
thereof cannot be performed until just before an end of an exhaust
process of the last cylinder in the firing order, causing a long
rest period of each heat exchanger, and each heat exchanger is thus
cooled during the period to reduce heat recovery efficiency.
Further, if the former is for vehicle use, it has problems that an
evaporator is provided in each cylinder to increase a size of an
engine itself, for example, by increasing an interval between
adjacent cylinders for the evaporator to be mounted, and that the
evaporator occupies a large space in an engine compartment to
result in an impediment to securing spaces for other components to
be located.
On the other hand, the latter has a problem that when a collecting
portion is formed at a long distance from an exhaust port in order
to avoid exhaust interference, and an evaporator is provided in the
collecting portion, temperature of exhaust gas decreases to reduce
heat recovery efficiency by the evaporator. On the contrary, when
the collecting portion is provided at a short distance from the
exhaust port without considering the exhaust interference in order
to utilize high-temperature exhaust gas, the exhaust interference
reduces output of the internal combustion engine and thus exhaust
pulses, thereby reducing the heat recovery efficiency by the
evaporator.
DISCLOSURE OF THE INVENTION
The present invention has an object to provide a waste heat
recovering device for a multi-cylinder internal combustion engine
in which output of a multi-cylinder internal combustion engine is
rarely reduced, and the number of heat exchangers is reduced
compared to the number of cylinders of the engine to reduce rest
periods of the heat exchanger and reduce spaces occupied by the
heat exchanger.
To attain the above described object, the present invention
provides a waste heat recovering device for a multi-cylinder
internal combustion engine including one or more collecting pipes
that are collection of a plurality of exhaust pipes unlikely to
cause exhaust interference, among a plurality of exhaust pipes
extending from cylinders of a multi-cylinder internal combustion
engine, a heat exchanger for recovering heat of exhaust gas being
provided in the one or more collecting pipes.
When exhaust pipes extending from a plurality of cylinders whose
exhaust periods partially overlap are collected with their lengths
reduced, exhaust interference occurs to reduce output of a
multi-cylinder internal combustion engine. However, even when
exhaust pipes extending from a plurality of cylinders whose exhaust
periods do not overlap are collected with their lengths reduced,
exhaust interference is unlikely to occur, thus rarely reducing the
output of the multi-cylinder internal combustion engine.
Configured as described above in this view, the output of the
multi-cylinder internal combustion engine is rarely reduced even
when the exhaust pipes are collected with their lengths reduced.
Further, the number of the heat exchangers is smaller than the
number of the cylinders, thus rest periods of the heat exchangers
can be reduced.
Reduction in the length of the exhaust pipe as described above
allows the exhaust gas to be introduced in the heat exchanger with
its temperature reduction minimized, and also the rest period of
the heat exchanger is reduced, thereby allowing increase in heat
recovery efficiency of the exhaust gas. Further, attendant on the
reduction of the heat exchangers, spaces occupied by them can be
reduced to achieve reduction in size and cost of the device, which
is suitable for vehicle use.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a waste heat recovering device for an
internal combustion engine;
FIG. 2 schematically illustrates a relationship between an in-line
four-cylinder internal combustion engine and an evaporator;
FIG. 3 illustrates a relationship between a crank angle in the
in-line four-cylinder internal combustion engine and an exhaust
period of each cylinder;
FIG. 4A and FIG. 4B illustrate relationships between operating
periods and rest periods in a plurality of evaporators;
FIG. 5 illustrates a relationship between a crank angle in an
in-line three-cylinder internal combustion engine and an exhaust
period of each cylinder;
FIG. 6 schematically illustrates a relationship between an in-line
two-cylinder internal combustion engine and an evaporator;
FIG. 7 schematically illustrates a relationship between the in-line
three-cylinder internal combustion engine and an evaporator;
FIG. 8 schematically illustrates a relationship between an in-line
five-cylinder internal combustion engine and an evaporator;
FIG. 9 schematically illustrates a relationship between an in-line
six-cylinder internal combustion engine and an evaporator;
FIG. 10 schematically illustrates a relationship between an in-line
eight-cylinder internal combustion engine and an evaporator;
FIG. 11 schematically illustrates a relationship between a V-type
six-cylinder internal combustion engine and an evaporator;
FIG. 12 schematically illustrates a relationship between a V-type
eight-cylinder internal combustion engine and an evaporator;
FIG. 13 schematically illustrates a relationship between a V-type
ten-cylinder internal combustion engine and an evaporator; and
FIG. 14 schematically illustrates a relationship between a V-type
twelve-cylinder internal combustion engine and an evaporator.
BEST MODE FOR CARRYING OUT THE INVENTION
In FIG. 1, a waste heat recovering device 2, to which Rankine cycle
is applied, of a multi-cylinder internal combustion engine 1
comprises an evaporator 3 as a heat exchanger for generating a
vapor having a raised temperature and a raised pressure, that is, a
raised temperature/pressure vapor, using waste heat, for example,
the exhaust gas of the internal combustion engine 1 as a heat
source; an expander 4 for producing output by expansion of the
raised temperature/pressure vapor; a condenser 5 for liquefying a
vapor having a dropped temperature and a dropped pressure, that is,
dropped-temperature/pressure vapor discharged from the expander 4
after the expansion; and a supply pump 6 for supplying liquid, for
example, water, from the condenser 5 to the evaporator 3.
In FIG. 2, a multi-cylinder internal combustion engine, in this
case, an in-line four-cylinder internal combustion engine 1 has
first to fourth cylinders I to IV, and their firing order is the
first cylinder I, third cylinder III, fourth cylinder IV, and
second cylinder II as denoted by Arabic numerals in parentheses (1)
to (4) in FIGS. 2 and 3. In FIG. 3, an angle line a is a diagram of
a lift of an exhaust valve, thus an interval from one edge to the
other edge of the angle line a shows a period when the exhaust
valve is opened, that is, an exhaust period b. Therefore, exhaust
periods b of the first and third cylinders I, III; the third and
fourth cylinders III, IV; the fourth and second cylinders IV, II;
and the second and first cylinders II, I partially overlap, so that
exhaust interference occurs when, for example, exhaust pipes
extending from the first and third cylinders I, III are collected
with their lengths reduced.
In this case, for the first and fourth-cylinders I, IV and the
second and third cylinders II, III, their exhaust periods b do not
overlap and hence, the exhaust interference rarely occurs. Thus, as
shown in FIG. 2, exhaust pipes 11, 14 extending from the first and
fourth cylinders I, IV and exhaust pipes 12, 13 extending from the
second and third cylinders II, III unlikely to cause the exhaust
interference are shortened, and two collecting pipes 7 that are
collection of the exhaust pipes 11, 14 and 12, 13, respectively are
formed and provided with first and second evaporators 21, 22,
respectively.
By the configuration as described above, even when the exhaust
pipes 11, 14 and 12, 13 are collected with their lengths reduced,
the exhaust interference is unlikely to occur, thus rarely reducing
the output of the internal combustion engine 1. The number of
evaporators is "two", which is smaller than "four", the number of
cylinders, so that rest periods of the first and second evaporators
21, 22 can be reduced.
FIG. 4A shows operating periods and rest periods of the first and
second evaporators 21, 22 in an embodiment in FIG. 2, and FIG. 4B
shows operating periods and rest periods of the first to fourth
evaporators in a conventional example. In the drawings, reference
characters I to IV denote the first to fourth cylinders in an
exhaust process. As is clearly shown in FIGS. 4A and 4B, the rest
period of each of the first and second evaporators 21, 22 in the
embodiment is one third that of the conventional example since the
first and second evaporators 21, 22 are alternately operated.
Reduction in lengths of the exhaust pipes 11 to 14 as described
above allows the exhaust gas to be introduced in the first and
second evaporators 21, 22 with its temperature reduction minimized,
and also the rest periods of the first and second evaporators 21,
22 are reduced, thereby allowing significant increase in heat
recovery efficiency of the exhaust gas.
Further, attendant on the reduction of the heat exchangers, spaces
occupied by them can be reduced to achieve reduction in size and
cost of the device, which is suitable for vehicle use.
The above described exhaust interference becomes a problem for
in-line four- or more cylinder internal combustion engines, and in
a three-cylinder internal combustion engine, explosion intervals
are long at crank angles, so that exhaust periods do not partially
overlap among first to three cylinders I to III as shown in FIG. 5,
thus exhaust interference is unlikely to occur. This applies to a
two cylinder internal combustion engine. The present invention is
also applied to a two- or three-cylinder internal combustion
engine.
FIGS. 6 to 10 show examples of various kinds of in-line
multi-cylinder internal combustion engines 1 to which the invention
is applied. In the drawings, Roman numerals I to VIII denote first
to eighth cylinders, Arabic numerals in parentheses denote firing
order of the cylinders, reference numerals 15 to 18 denote exhaust
pipes, and reference numerals 23 and 24 denote third and fourth
evaporators. In an in-line five-cylinder internal combustion engine
1 in FIG. 8, an exhaust pipe 13 of a third-cylinder III is
separately provided with a third evaporator 23. In an in-line
three-or less cylinder internal combustion engines, the exhaust
pipes are shortened and collected into one. On the other hand, in
an in-line four-, five- or six-cylinder internal combustion engine,
with respect to an nth cylinder in the firing order, a cylinder to
be collected is an n+2 or more cylinder in the firing order with
one or more places in the firing order skipped. In an in-line
seven-, eight- or nine-cylinder internal combustion engine, with
respect to an nth cylinder in firing order, a cylinder to be
collected is an n+3 or more cylinder in the firing order with two
or more places in the firing order skipped. In an in-line ten-,
eleven- or twelve-cylinder internal combustion engine, with respect
to an nth cylinder in firing order, a cylinder to be collected is
an n+4 or more cylinder in the firing order with three or more
places in the firing order skipped.
FIGS. 11 to 14 show examples of various kinds of V-type
multi-cylinder internal combustion engines to which the invention
is applied. In the drawings, reference character L denotes a left
column and reference character R denotes a right column, and Roman
numerals and Arabic numerals in parentheses denote the same as
described above. In this case, assuming that each of the left
column L and the right column R is an in-line engine, cylinders to
be collected are selected in accordance with the case of the
in-line multi-cylinder internal combustion engine.
From the in-line multi-cylinder internal combustion engines 1 in
FIGS. 6 to 10 and the V-type multi-cylinder internal combustion
engines 1 in FIGS. 11 to 14, it is apparent that the number of
evaporators is smaller than the number of cylinders.
* * * * *